The Dr. Is In: Taking the Mystery Out of Vitamin B-12
Posted Aug 10 2011 2:13pm
OK, first of all: absolutely fantastic responses to Courtney and Sarah’s thoughtful and illuminating guest post! This was a departure from the usual Green Recovery story, to be sure, but I think it was one of the strongest entries so far. I appreciate all the comments. The post has also inspired me to write a post I’ve been meaning to write for a while, on sex/sexuality and ED recovery, so you can expect that before too long.
I’ve got another guest post for you today, but this one’s in a totally different vein. For a long time now, I’ve been hoping to start a “ask your doctor” series here on CR, in which I ask a real life physician to answer some of my readers’ most pressing health and wellness questions. I do the best I can when I get health inquiries, but my knowledge base has limits (hence the whole post-bacc/med school thing), and there’s nothing I hate more than posturing as an expert when I’m missing the necessary expertise. So from now on, I’ll be fielding certain important health inquiries to an MD who’s capable of explaining the answers to us simply and informatively.
That MD is my good friend, Dr. Stuart Seale. Dr. Seale first commented on my blog about a year ago. At the time, I was toying with the idea of a career in medicine, but I was still too riddled with doubts to take it very seriously. Months later, when I was ready to commit to a post-bacc, I sent Dr. Seale a very candid (and, I daresay, helpless) email voicing some of my biggest fears: was I too old? Would the debt crush me? Would I be able to have kids in my thirties, if indeed I wanted to? And so on. Dr. Seale responded with what is by far the most insightful and inspiring email I’ve ever gotten from a near-stranger, urging me to pursue this crazy plan. We’ve been correspondents and supporters of each others’ work ever since, and I hope I’ll be able to rely on Dr. Seale’s expertise and confidence as I continue my studies (especially as I head into my Orgo/ Bio year—he was a biochem major!).
In the future, I hope to get Dr. Seale’s opinion on some complex and unexpected nutrition topics, but I decided to start with basics: B-12. It’s the Vitamin I am most often asked about (for good reason; it can’t be supplied in a vegan diet without either supplementation or certain fortified foods), and no matter how many times I offer up the standard feedback, readers continue to be confused about it. For instance, they wonder how “natural” a vegan diet can be, if it lacks an essential vitamin? I’m so glad to have Dr. Seale here today to put some of our concerns to rest, and so that he can give us some essential tips on how to supplement properly.
Without further ado, the doctor is in.
Taking the Mystery Out of Vitamin B12by Stuart A. Seale, M.D.
For those who follow a plant-based diet, it’s not uncommon for friends and family to voice concern over a number of nutritional issues that aren’t grounded in fact. “Where will you get your protein?” or “You’ve got to drink milk to get calcium!” are comments often heard. In the same vein, when it’s learned that a vitamin B12 supplement is routinely recommended for vegetarians, and especially vegans, many are quick to conclude that a plant-based diet is inferior. After all, if a total plant-based diet is so healthy, then why doesn’t it supply all essential nutrients and micronutrients? This has led to confusion, even among vegans. So let’s take a look at the science regarding B12 and dispel some myths along the way.
Vitamin B12 functions as a co-factor in numerous metabolic and physiologic events critical to human health. It plays a role in the proper production of red blood cells, and a deficiency can lead to megaloblastic anemia. Vitamin B12 is also vital for proper nerve function. Without it, various neurologic and psychiatric symptoms such as numbness, weakness, shakiness, unsteady walking, mood disturbances, and even dementia can develop. There is also good evidence that vitamin B12 improves vascular health because of the role it plays in reducing blood homocysteine levels. High homocysteine can damage arteries, increasing the risk for heart attack and stroke. Other effects currently being researched include the role of vitamin B12 in reducing the risk of breast cancer, cholesterol, and stroke recurrence.
Vitamin B12 is an essential micronutrient for humans. “Essential” means that it must come from external sources – we can’t manufacture it in our bodies using other nutrients as building blocks. The vitamin, in its full form, must therefore be supplied dietarily. This fact is what creates a potential rub for vegetarians, because no plant foods serve as a reliable source for B12. It’s only found predictably in animal foods – meat, eggs, and dairy.
Does this mean that we weren’t designed to be vegetarians, and that plant-based diets are inferior? In order to answer these questions, we need to look at the ultimate source for all vitamin B12, which is bacteria. The vitamin is made in nature only by bacteria that reside in soil, the upper intestinal tracts of ruminant animals (cows, sheep, deer, etc.), and also the lower intestines of animals. In the case of ruminants, the B12 that is made by the bacteria residing in their stomachs can then be absorbed into their tissues. In addition, the food they eat is contaminated with soil, which contains vitamin B12. Livestock are also fed B12 fortified foods to boost tissue levels. For wild, non-ruminant vegetarian animals there likely is enough ingestion of bacteria from foods contaminated with soil to provide adequate B12. In the case of wild, carnivorous animals, B12 is supplied from the liver (the animal storage organ for excess B12) and the intestinal bacterial of their prey.
The daily requirements of B12 for humans is very low, and in the past when we didn’t live in such a sterile and germophobic society it is likely that soil and other bacterial contamination of plant foods provided all the B12 needed. But our environments are different in the modern age. We are not only living much more sanitarily and bacteria-free, but our agricultural soils have also become sterilized. Of course, there is still the bacterial production of B12 in the lower intestinal tracts of animals, including humans, but we can’t absorb the vitamin from that location. However, undoubtedly much of the B12 found in animal foods is derived from intestinal bacterial contamination during the slaughter process.
There is an abundance of nutritional research demonstrating the benefits of eating whole plant foods, even if no animal foods are included. Humans are perfectly capable of eating a totally plant-based diet and maintain superior health while doing so. In our former agrarian society when bacteria-rich soils were worked by hand, there simply wasn’t an issue with humans getting enough B12, because it was supplied by soil contamination of our foods and skin. The issue of vegans requiring vitamin B12 supplementation is therefore not an indicator of a plant-based diet being inferior or unhealthy. The two really have nothing to do with each other. The fact that modern vegans require B12 supplementation is related to the sterility of our environment, not to the overall nutritional quality of the foods we eat. Humans haven’t changed, but our environment has.
To be certain vitamin B12 deficiency doesn’t occur, taking a supplement of B12, as little as 25 to 100 micrograms per day, is all that’s needed. Larger doses, up to 1,000 micrograms per day are commonly recommended but probably not necessary. Supplements of B12 may be labeled as cobalamin, cyanocobalamin, or methylcobalamin and there will be very little difference regarding their effectiveness when taken routinely. While both vegetarians and vegans should supplement with B12, it’s even more critical that vegans take a supplement. Some are adverse to taking a supplement produced from a bacterial source, but look at it this way – you’re getting in a purified pill form what our ancestors got from under their fingernails.
Enjoy all of the benefits of eating plant-based: less tendency for being overweight; lower risk of heart attack, stroke, hypertension, cancer, and chronic disease in general; and being kind to the environment and other living creatures. Just don’t forget to take your B12!
Stuart A. Seale, M.D., Diplomate American Board of Family Medicine, graduated from Loma Linda University School of Medicine in 1979, then completed a Family and Community Medicine residency at the University of Missouri in 1983. He established and maintained a solo office family practice in Springfield, Missouri for 21 years before joining Ardmore Institute of Health as Clinic Director, educator, and staff physician for Lifestyle Center of America. He is currently Vice President and Chief Medical Officer for Ardmore Institute of Health, as well as Medical Director for AIH’s Renovo Clinic in Gilbert Arizona. He is also an Adjunct Assistant Professor in the Department of Preventive Medicine at Loma Linda University School of Medicine. He joined the American College of Lifestyle Medicine in 2006, and currently serves on the Board of Directors for the ACLM Foundation. Dr. Seale has a passion for treating chronic disease through lifestyle behavior modification, and wishes to influence the practice of medicine in America, as well as American culture itself. To this end, he has co-authored two books related to healthy lifestyle – The 30-Day Diabetes Miracle , and The Full Plate Diet . He and his wife Sandra reside in Sedona, Arizona.
Fabulous post, Dr. Seale! And useful for me, too. In my first couple of years as a vegan, my B-12 levels were always off the charts, in spite of the fact that I rarely supplemented and drank few fortified beverages. So I got into the lazy habit of not taking a supplement. Lately, I’m more determined to take at least a moderate dosage, because even if my body seems to store B-12 for the moment, that won’t be true forever, and there’s no harm in prevention.
OK, friends, this part’s exciting: now that we have Dr. Seale as a regular CR contributor, I welcome you all to send in questions (you can email them to me, or tweet me, or you can leave comments on this post) that you’d like for Dr. Seale to respond to. Of course I still welcome you to send me questions regarding nutrition, cooking, raw food, ED’s, and female health, but be aware that you now have another resource when it comes to hard questions about biology and medicine.
Also, I encourage you to get to know Dr. Seale in person. His twitter handle is @DrSeale, his blog is Dr. Seale Weighs In, and you can read about his work at the Renovo Clinic , where he helps to share his passion for chronic disease prevention and treatment through lifestyle choices, here .
Send in those questions. And please, wish me luck: after five warp speed weeks, my big chem final is tomorrow at 8 am!